GMAT Question of the Day (Jan 3): Arithmetic and Sentence Correction

1000 dollars were converted into pounds and then the pounds were converted back into dollars at the same exchange rate of pounds per dollar. If a commission of is levied on any exchange operation, what dollar amount was left after the exchanges?

Recent cosmological advances have made it possible to observe stellar objects that would only a decade ago have been unable to be viewed.

(A) it possible to observe stellar objects that would only a decade ago have been unable to be viewed
(B) it possible to observe stellar objects that would have been invisible only a decade ago
(C) possible that one can observe stellar objects invisible only a decade ago
(D) possible the observing of stellar objects that were not capable of being viewed only a decade ago
(E) possible the observing of stellar objects that only a decade ago would not have been able to be viewed